Closed loop multi-pass sorbent based hemodialyzers have the advantage of being portable and compact while being able to regenerate dialysate using a plurality of sorbents. Typically these sorbents are used in disposable cartridges/canisters and comprise sorbent composition layers similar to those used in prior systems, such as urease, zirconium phosphate, hydrous zirconium oxide and activated carbon. As spent dialysate comprising urea, diffused from impure blood in the dialyzer, passes through prior art sorbent cartridges, carbon dioxide and ammonia are produced as two unwanted byproducts of the chemical reactions. While ammonia is adsorbed in zirconium-based cartridges, carbon dioxide is not captured, mixes in the dialysate, and manifests as carbon dioxide bubbles in the dialysate circuit. Large amounts of carbon dioxide leave the liquid phase and interfere with the smooth pumping of dialysate. In addition other dissolved gases may exit from the liquid phase during processing adding to the volume of gas in the system.
Accordingly, there is a need for a degassing device that can remove unwanted carbon dioxide, and other gases, from the dialysate circuit. The degassing device needs to be particularly suitable for a portable hemodialyzer, where the orientation of the dialyzer should not disrupt or degrade the efficiency of the degassing device. At the same time, the degassing device needs to be small in size, light and low cost so that it can be a disposable component.